The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. Conventional vehicular fuel systems, such as those installed in automobiles, may employ a “return fuel system,” whereby a fuel supply tube or line is utilized to supply fuel from a fuel tank to an engine and a fuel return tube or line is utilized to return unused fuel from the engine to the fuel tank.
Typically, more modern vehicles employ a “returnless fuel system” that may be either mechanically or electrically controlled. In many returnless fuel systems, such as a mechanical returnless fuel system (“MRFS”) a fuel pump continuously pumps a constant flow of fuel from a fuel tank to the engine. In another type of returnless fuel system, such as an electronic returnless fuel system (“ERFS”), the voltage across the fuel pump is controlled to vary the fuel pumped to the engine. A pressure regulator controls the pressure of fuel directed to the engine, and discharges excess fuel back into the fuel tank. This eliminates the need for a return line, hence the term “returnless fuel system.”
When the engine is operating, fuel is delivered to the engine at a relatively low pressure, for example, at 400-450 kilopascals (kPa). The engine may then be turned off, and for a time period after the engine is turned off but still radiating heat, the fuel remaining in the fuel injector rail and the fuel line may be heated by the engine, other hot components of the vehicle, and/or high ambient air temperatures. Under these conditions, low pressure fuel in the fuel rail or any fuel lines may vaporize. As such, fuel vapor in the injector rail or fuel lines can cause vapor lock, which in turn, may hinder or prevent ignition or combustion during an attempted engine restart.
Prior known fuel systems lack a satisfactory means for managing fuel pressure and flow within the fuel system, both during and after an engine's operation, in an efficient, space-conscious manner.